The Passover Seder is one of the most recognized and widely practiced of Jewish rituals, yet had our ancestors visited one of these modern-day celebrations, they would be baffled.

Not only does our modern Seder wildly diverge from the Passover of old: during antiquity itself the holiday underwent radical changes. Below we chart as best we can - considering the shortage of historical documentation - the origins of Passover, from the dawn of Israelite people to the destruction of the Second Temple in 70 CE, and the consequent establishment of the embryonic Passover Seder, which modern Jews would recognize.

As the centralized Israelite state took shape about 3,000 years ago, , the religion of the people varied from place to place and took variegated forms, hints of which we can see in the Bible, virtually the only historical narrative we have of this period. Among the different folk beliefs and frankly polytheistic practices these proto-Israelites practiced, the springtime rites seem to have had special status. Two of these rituals would later become subsumed by Passover: Pesach and Hag Hamatzot.

Pesach was a pastoral apotropaic ritual, that is: its purpose is to ward off evil. It was carried out by the semi-nomadic segment of Israelite society that subsisted on livestock. Spring was a critical time of the year for them, a time of lambing and a sign that soon they would have to migrate to find a summer pasture for their flock.

In order to protect their flocks, and families, from the dangers ahead, they would slaughter their flock’s newest addition as an offering, either a lamb or a kid, in a bloody ritual followed by a family feast.

The origin of matza

Hag Hamatzot, on the other hand, was celebrated by the settled segment of Israelite society, who lived in villages and who drew their subsistence from farming. For them too spring was crucial, meaning the start of the harvest, of the cereals on which they depended.

Of the cereals grown by the ancient Israelites in this period, the first grain to be ready for harvest was barley. Although this made for inferior bread, it was highly prized: not rarely, by the spring harvest, the last year’s stores had been already depleted and hunger took grip of the land.

This new bread would have been unleavened, as the leavening used at the time was a portion of dough set aside from the last batch of bread. But this would have been unavailable due to the gap created by the empty stores. Add to this the fact that barley flour hardly rises anyway, and that the baking techniques of the time would have made even the superior bread made of wheat flour flat and hard, and you’ve got matza.

Still, when hungry even matza is a cause for celebration and one could imagine that the communal threshing grounds were filled with joy, cheer, and jubilation.

The holidays are merged

As the monarchy was established and a centralized religion took form, the two holidays began merging into one. The process was a gradual one, which culminated in both converging to the full moon in the middle of the spring month of Nisan.

The location of the celebrations was moved from the home and the community to the Temple in Jerusalem.

No doubt, an important milestone in this process took place in the reforms of the 16-year-old King Josiah in 622 BCE, as described in chapter 22 of the Second Book of Kings.

We are told that Josiah ordered the temple be renovated. and that During this process, as Hilkiah the high priest was clearing the Temple’s treasure room, “The Book of the Law,” - believed to be an early version of the Book of Deuteronomy - was found. This led to a series of reforms carried out by Josiah to bring the land into accord with the newly -discovered divine ordinances.

A major part of these reforms was the reform of Passover: “And the king commanded all the people, saying, Keep the passover unto the Lord your God, as it is written in the book of this covenant.” (23:21)

It was no longer supposed to be a family affair but a centralized national observance: the Book of Deuteronomy clearly stipulates that the Pesach sacrifice may not be made “within any of thy gates” but rather at the Temple. (16:5-6)

Pilgrimage to Jerusalem

Following Josiah’s reforms, the holiday took the form of a mass pilgrimage to Jerusalem. The people would bring their paschal lamb (or kid) to be sacrificed at the Temple.

The feast of unleavened bread began the day after. All were commanded to avoid eating leavened bread for a week, though it seems that this wasn’t accompanied by any special practices in the Temple; the Israelites would probably have followed this precept on their way home and at their homes themselves.

Not much more is known about the celebration at this time. This was apparently the time in which the story of the exodus from Egypt was introduced [link http://www.haaretz.com/archaeology/.premium-1.584911 . But this form of practice didn’t last long. In 586, BCE the Babylonians sacked Jerusalem, the Temple was destroyed and the period in Jewish history called the Babylonian Captivity began.

Bondage in Babylon

It is during this time, when the elite of Judean society was in the relatively literate and cosmopolitan Babylonia and had they had no Jerusalem Temple on which to focus their religious fervor, that the writing of many of the Biblical texts took place. This includes the Book of Exodus, the central tale of Passover. Among other things, the story would have united the people and appealed to its writers themselves, as they found themselves in bondage in a foreign land, hoping to be delivered by God and returned to their homeland.

They were indeed delivered, in 538 BCE, when Cyrus the Great, King of Persia, defeated the Babylonians, and proclaimed that the Jews could return to their homeland and rededicate their temple. Upon their return and the dedication of the new temple in 516 BCE, the holiday of Passover was reinstated. “And the children of the captivity kept the passover upon the fourteenth day of the first month...and kept the feast of unleavened bread seven days with joy.” (Ezra 6:19-22)

Following the rededication of the Temple, the Judeans would come to Jerusalem a few days before the holiday each year. They would prepare for the holiday by going through rigorous purity rituals. Entering the Temple compound in groups, the head of each household would hand their animal offering to the priests, who killed the animal, drew its blood and sprayed it on the altar. Then the carcass was returned to the family that had given it and they would roast it and eat it within the confines of the Temple.

The next day the people dispersed, though they would continue to eat unleavened bread for another week.

This form of Passover continued until the Maccabean Revolt erupted in 167 BCE. The celebration of Passover at the Temple had to stop, briefly, until Jerusalem was recaptured by the Maccabbees and the Temple was rededicated in 165 BCE. At this time Passover underwent further change.

The Hasmonean reform

Under the new Hasmonean regime, the sacrifice of the Pesach offering was done by the head of the household himself, not by the priests. On the other hand, during the week following Pesach, special sacrifices were given, and these were sacrificed by the temple staff - the priests and the Levites.

Another innovation that seems to have arisen under the Hasmonean Dynasty was the singing of songs praising God and the drinking of wine during the family meals, as well as some kind of public celebration at the end of the week of Hag Hamatzot.

The civil war that resulted from the murder of Julius Caesar in 44 BCE led to the demise of the Hasmonean Dynasty and the ascent of Herod the Great to the Judean crown in 37 BCE, as a puppet ruler of Rome. This had little effect on Passover, which continued pretty much as it was under Hasmonean rule. However, the vast numbers of Jews coming from throughout the Roman Empire forced change, as there was no longer room for everyone to have their paschal mean within the confines of the Temple. The rules were relaxed to the extent that the meal could be eaten anywhere within Jerusalem.

But this massive influx of Jews to Jerusalem made the Roman authorities uneasy. Several sources from this period report that the Jerusalem garrison was fortified during Passover to prepare for any unruliness.

The Passover meal in this form was the meal described in the New Testament as Jesus’ last supper.

In 66 CE, religious tensions between Greek and Jewish citizens, and protests over the heavy tax burden, boiled over into the Jewish rebellion against Rome. This rebellion was put down in 70 CE. Roman legions under Titus retook Jerusalem, destroying the Temple and much of the rest of the city. Passover was never to be celebrated as it had been again.

In Yavne, a rabbinical school lead by Rabbi Johanan ben Zakai and Rabban Gamaliel II, set out to forge a new Judaism adapted to a post-Temple world. Among their innovations, which were later redacted into the Mishnah, was the embryonic form of the Passover Seder we know and celebrate today.